The art of adding agents to foodstuffs has advanced in many directions calling for the encapsulation of organoleptically offensive nutrients. This invention relates to a method whereby a number of nutrients, particularly thiamine, can be effectively fixed in compatible encapsulating mediums for incorporation in various food systems, especially aqueous food systems.
Thiamine has an extremely strong characteristic yeasty, fishy odor which has greatly limited its use in food systems such as dry beverage mixes whereas the art of encapsulating medicaments for pharmaceutical preparations tolerate some trace of thiamine character. The formulation of a comestible has a much more demanding threshold tolerance to the organoleptic impact of offensive nutrients such as thiamine. The art has long sought and failed to provide a means whereby thiamine can be commercially combined in a food system without contributing its characteristic odors and taste. The need for stabilization of thiamine in a fixation which substantially completely inhibits sensory perception of the thiamine in both aqueous and non-aqueous food systems presents a challenge which available art practices have not heretofore been satisfactorily met.
A key limitation is the ability that provides stability against thiamine odors in both aqueous as well as dry food systems. Thiamine degradation odors are particularly objectionable in certain food applications such as cereals and beverages where the consumer senses either flavorful cereal notes or in the case of beverage products fruit or like flavor notes which are both aromatic and flavor perceptible. In such products it is important to have a flavor characteristic wherein there is a substantially neutral presence of thiamine or any thiamine degradation odors. Additionally, such thiamine fixations should be compatible with other nutrients that may desirably be mixed in the food system such as ascorbic acid or mineral salts. The effective partitioning of the thiamine fixations so that in the beverage state or other reconstituted aqueous medium the thiamine is not available for any organoleptic contribution or reaction with such other nutrients is a desired characteristic of the thiamine fixation.
To be useful the coating applied to thiamine must be of such a nature and an amount that it permits the thiamine to be bio-available after ingestion. Additionally, regulatory involvement in the area of nutritional fortification of foods also requires that any coating medium be substantially free of questionable residues employed to implement such coating materials. Thus the coating agents, as well as the solvents employed to facilitate distribution of the coating agent, should preferably be on the GRAS (generally recognized as safe by the Food & Drug Administration) list.
Prior art attempts have met with limited success regarding techniques which would produce an acceptable thiamine coated product. One example is disclosed in Food Additive Petition No. 4A3020. According to the disclosure, thiamine was coated with a combination of ethyl cellulose and a blend of distilled glyceryl monostearate and propylene glycol monostearate together with hydrogenated vegetable oil. A combination of methylene chloride and ethanol was used to dissolve the coating materials. The dissolved coating materials were contacted with the thiamine crystals and dried utilizing a fluidized bed coating apparatus. The microencapsulated thiamine was intended for use in dry beverage mixes, dry breakfast cereals, dry pudding mixes and dry gelatin mixes. The limitation of that process, however, was that to achieve adequate protection of the thiamine the coating material had to comprise 80% of the total weight of the encapsulated product. Additionally, this high proportion of coating required process times typically in excess of 50 hours.
The utilization of ethyl cellulose in another prior art attempt to encapsulate thiamine is disclosed in U.S. Pat. No. 3,821,422 to Morse. The thiamine was microencapsulated with a coating of ethyl cellulose dissolved in cyclohexane and hexane. The product was to be used in the preparation of cake mixes. Accordingly, the thiamine was protected only in neutral or alkaline conditions and was released as acid in systems such as gastric fluid.
Other prior art attempts relate to the encapsulation of a variety of foods and particularly pharmaceutical compositions. For example, U.S. Pat. No. 2,921,883 to Reese relates to the use of a coating material for prolonging the release of medicaments in the gastrointestinal tract. The material is coated in the form of a pellet and is typically 500 microns in diameter. According to the examples, the medicaments were placed in a pan and then covered with a lipid/cellulose derivative solution and subsequently dried. Typical coating levels disclosed are 2 to 15% of coating by weight of the total composition. Such a system is unsuitable for use in beverages since the final product size is too large.
Accordingly, it becomes desirable to provide an alternative coated thiamine product and a method for obtaining it wherein the coated product has a broad range of uses including stability in dry beverage mixes and the beverage derived from those mixes. In the case of dry beverage mixes and the like, the fixed thiamine should be capable of withstanding extended storage conditions wherein the temperature exceeds 100.degree. F. The coating should be stable at such elevated storage temperatures so that the encapsulated product retains its functionality and does not result in undesirable organoleptic factors in the reconstituted product. Additionally, the thiamine fixation should be such that the coated form has a physical strength sufficient to permit the encapsulated product to withstand the abrasion or attrition which can be enduced during blending and storage with other constituents of the product.
Regarding a final product which is a beverage or aqueous foodstuff, especially those with a pH of below about 4.5, it is desirable that the thiamine in the final product remain stable for at least 25 hours and preferably at least 48 hours without contributing offensive thiamine odors.